The present invention relates to a method for unloading open containers of uncompacted or loosely compacted tobacco bales.
Currently it is usual to place tobacco, in its various forms (and therefore in strips, cut stems, expanded, uncompacted or loosely compacted, etcetera) into suitable and appropriately prepared containers which are substantially shaped like a parallelepiped.
These containers, which have standard shapes in order to allow uniform transport, storage and processing of the tobacco, can be constituted by a box-like cardboard structure of suitable thickness having an openable upper end.
These cartons can then be reused after they have been emptied of their content.
As an alternative, the containers are made of wood or metal with suitable side walls and a suitable bottom and with a generally open upper side.
Said containers are sometimes provided with wheels which are applied to their bottom for better handling and with lateral profiles to make it easier for handling units to engage them.
The production cycle of tobacco manufacturing and processing companies requires at several stages operations for tipping and emptying the containers.
Machines are known for this purpose which are constituted by an engagement device, such as a substantially L-shaped rigid arm, on a wing of which the lower base or the bottom of the container, which is open, is rested and engaged. The other wing of the arm is pivoted, at one end, to a pivot so as to allow to tip said container, for example to unload the tobacco onto a suitable conveyor belt which is arranged to the rear and above said arm.
It is also known to provide arms which are fixed, at the tipping axis, to lifting devices which are suitable to produce a lifting movement before the above-mentioned tipping movement, again using an open container.
This method used to unload conventional containers entails considerable drawbacks. First of all, the uncompacted or loosely compacted tobacco is unloaded from the container at a certain height above a platform or conveyor belt, as in the described case; the impact entails a deterioration of said tobacco, which is shredded further, also forming dust.
The resulting piece size reduces the quality of the subsequent processes, since such processes occur in a less than optimum manner because they are usually preset for a given piece size or shape of said tobacco.
Moreover, dust is released into the surrounding environment when the tobacco falls from the container, requiring the use of localized suction systems which are not always able to aspirate the dust completely.